Eye tomographs, such as an optical coherence tomograph (OCT), allow three-dimensional observation of the interior of a retinal layer. The tomographs have recently attracted attention because of the usefulness in correct disease diagnosis. An example of the OCT is a time domain OCT (TD-OCT) in which a broadband light source and a Michelson interferometer are combined. This OCT is configured to scan the delay of a reference arm to measure the interference of light with back-scattered light from a signal arm, thereby obtaining information on depth resolution. It is, however, difficult for such TD-OCT to achieve high-speed image acquisition. Thus, a spectral domain (OCTSD-OCT) configured to obtain an interferogram using a beam splitter and a broadband light source is known as a method for acquire images at higher speed. Another example of the OCT is a swept source OCT (SS-OCT) that employs a method of measuring spectral interference with a single-channel light detector by using a high-speed wavelength-swept light source.
Diagnosis using tomograms acquired by such OCTs requires high-quality tomograms. To this end, PTL 1 discloses a method for super-resolution processing to acquire clear images in tomography.
The degree of progression of a disease and the degree of recovery after treatment have conventionally been evaluated by checking the thickness of a retinal layer in a tomogram. However, according to NPL 1, the recent progress of the OCTs tends to improve pathological understanding on an observation target in a tomogram by evaluating not only the thickness of a retinal layer but also a small lesion.